The present invention relates to a cutting device with a retractable blade, comprising a blade and a sleeve into which it is adapted to be retracted.
Cutting devices with retractable blades comprising a blade sliding in a sleeve with a slideway, are well known. For example, instruments of this type, called cutters, permit cutting paper, cardboard or any other material generally in the form of sheets or plates.
The blades used in these devices are very sharp to ensure effective cutting and they are generally interchangeable so as to maintain a completely operable instrument. Thus, these instruments are relatively dangerous and numerous accidents take place during use. Conventionally, the user must exert a strong pressure on the sleeve of the instrument and give it a rapid movement to obtain a clean cut of the material to be cut. Thus, when the contact of the blade with the material stops, the user must also stop moving said instrument with as much energy as what was necessary for cutting. However, generally, accidents take place when the contact of the blade with the material stops and, while still applying force, the user brings the blade toward himself.
A problem which arises and which the present invention seeks to solve, is thus to provide a cutting device with a retractable blade in which the blade retracts into the sleeve before a clumsy user can bring it toward himself or toward anyone else.
To this end, the present invention provides a cutting device with a retractable blade, comprising: blade support means, having means forming a drive abutment, adapted to slide along the axis of said sleeve between a first rest position in which the blade is retracted and a first working position in which the blade is extended beyond said sleeve, said support means being in said first working position, adapted to be brought from a second rest position to a second working position, spaced from the axis of said sleeve, by passing through a second intermediate position; first resilient return means adapted to hold said blade support means in said first rest position; controllable movement means mounted on said sleeve, adapted to coact with said support means and to bear against said drive abutment means to drive said blade support from said first rest position toward said first working position; abutment means adapted to receive said blade support means in said second working position to block them in translation; and the drive of the blade by means of said sleeve against a surface to be cut involving said support means in said second working position and giving rise to the disengagement of said controllable movement means engaged in said drive abutment forming means such that said resilient return means drive said blade support means into said first rest position as soon as the blade is no longer in contact with said surface and said abutment means free said blade support means which are brought from said second working position toward said second intermediate position.
Thus, a characteristic of the cutting device according to the invention, resides in the manner of coaction of the blade support means with the controllable movement means and with the abutment means, permitting simultaneously blocking the blade support means in translation in the second working position and the disengagement of the controllable movement means engaged in the means forming a drive abutment. In this way, as soon as the blade is no longer in contact with the surface to be cut, the abutment means free the blade support means which, driven by the resilient return means, return to the first rest position in which the blade is completely retracted into the sleeve. Thanks to this characteristic, the user of the device cannot wound himself because the blade retracts when it leaves the surface to be cut.
In a particularly advantageous way, said blade support means, having an upper portion and a lower portion, extend longitudinally and comprise a first end in which the blade is held in prolongation of said blade support means, an intermediate portion comprising said drive abutment forming means, and a second guide end for said support means. In this way, the blade support means are adapted to be guided in translation in the sleeve along their longitudinal axis between the rest position and the working position with the controllable movement means which are applied to the intermediate portion.
Preferably, the drive abutment means are constituted by two means forming lugs disposed on the lateral surface of said intermediate portion in its lower portion, opposite each other and whose abutment surface is substantially perpendicular to said support means. Thus, the lug forming means constitute stop points perpendicular to the longitudinal axis of the blade support means against which the controllable movement means bear when they are controlled in translation.
According to a preferred characteristic, said controllable movement means have a first portion projecting outside the sleeve to control them, and a second portion divided into two symmetrical branches facing each other, adapted to overlap said upper portion at least in said intermediate portion and said first end, the branches being adapted to bear against the abutment surfaces of the lug forming means. In this way, when the controllable movement means are driven in translation, the branches bear against the lug forming means and drive the blade support means toward said first working position in which the blade is outside the sleeve.
It will be understood that the second portion of the controllable movement means, thus necessarily permit the passage of the first end of the blade support means and hence of the blade such that they retract under the influence of the resilient means when the controllable movement means are held in the working position.
Preferably, said branches of said second portion of said controllable movement means are inclined relative to each other and relative to a plane of symmetry which separates them, and the side walls of said upper portion of said intermediate portion constitute frictional regions against which the branches are adapted to be applied to be spaced from each other when said blade support means are driven toward said controllable movement means, and to disengage from said lug forming means. Thus, the second portion of the controllable movement means provides a flared fork whose internal wall of the branches, at least in their medial portion, comes to bear against the upper sidewalls of the intermediate portion. Moreover, the end of the branches is adapted to be engaged in the means forming a drive abutment located in the lower portion of the intermediate portion, when the blade support means are in the first working position. In this way, the movement of the blade support means, substantially perpendicular to their longitudinal axis and toward the summit of the fork in which the branches come together, gives rise to the spacing of the branches of the fork and the release of the lug forming means. This situation takes place when the blade is applied against the surface to be cut after having driven the controllable movement means and as a result the blade support means. These latter are thus brought to said second working position.
According to an advantageous feature, the second portion of said controllable movement means between the branches of which said upper portion of said intermediate portion is adapted to be engaged, constitutes said abutment means adapted to block said blade support means in said second working position. Thus, when the blade is applied against the surface to be cut and the controllable movement means are held in their working position, the upper sidewalls of the intermediate portion come to nest between the branches of the fork and space them, but they also permit, as will be explained in detail in what follows, the blockage in translation of the blade support means relative to the controllable movement means.
It will be understood that when the application of the blade against the surface to be cut stops, the branches of the fork tend to tighten and to remove the blade support means. In this way, the blockage in translation stops and the blade support means are practically freed in translation.
Preferably, said first resilient return means is constituted by a helicoidal spring, which drives the blade support means to the rest position when it is freed relative to the fork.
Preferably, the device moreover comprises second resilient return means adapted to hold said controllable movement means in a rest position.
According to a preferred embodiment, the blade support means and the controllable movement means are adapted to be formed by molding.